The present disclosure relates generally to voltage clamps for control devices such as transistors and, more particularly, to a clamp assist circuit for the same.
Control devices, such as those used in power train high side and low side control circuits, are frequently required to dissipate energy within the control device. In some instances, the level of dissipation required exceeds the energy dissipation ability of an internal voltage clamp of control device, potentially damaging the internal electronics of the control device.
To address the energy dissipation needs, existing control devices utilize a recirculation diode that recirculates current and, in the process, dissipates energy within the recirculation diode. The recirculation diode is arranged in a voltage clamp configuration, and only recirculates current when the clamp voltage is exceeded. Existing recirculation diodes and clamp circuits typically have a relatively low clamp voltage, thereby limiting the maximum voltage that can pass through the control device, and thus be absorbed by the control device, to a low magnitude.
At the same time, in some control devices, a high clamping voltage is required in order to guarantee a fast dissipation of the stored energy. The voltage clamp including a recirculation diode utilized in existing systems lowers the clamping voltage, thereby slowing the rate at which the energy is dissipated.